Studies were directed toward determining the steps involved in the differentiation of B cells into immunoglobulin synthesizing and secreting plasma cells. Special emphasis was laid on developing new techniques to study the role of helper T cells, macrophages and suppressor cells in these immune regulatory processes and to define defects in these immunoregulatory cell interactions in patients with immune dysfunctions. Leukemias of both suppressor and helper T cells have been identified. Excessive numbers of suppressor T cells have been demonstrated in association with agammaglobulinemia and selective IgA deficiency. Excessive numbers of non-T cell suppressors have been demonstrated in multiple myeloma associated with immunodeficiency. Finally a deficiency of this immunoregulatory system has been demonstrated in animal models of auto-immunity. Developments of techniques for detection of circulating tumor-related antigens has also been an objective of this overall study. BIBLIOGRAPHIC REFERENCES: Waldmann, T.A., Broder, S., Krakauer, R., Durm, M., Meade, B., and Goldman, C.: Defects in IgA secretion in IgA specific suppressor cells in patients with isolated IgA deficiency. Trans. Amer. Assoc. Phy. 89: 215-224, 1977. Waldmann, T.A. and Broder, S.: Suppressor cells in the regulations of the immune response. Prog. Clin. Immunol. Schwartz, R. (Ed.), vol. 3, pp. 155-199, 1977.